Modems:  Rockwell and MX-COM,

We are using the Rockwell RC224ATL for an embedded 1200 baud FSK modem.  It
allows for a serial or parallel interface and operation to 2400 baud.  If
you are connecting it to a telephone system, it has the capability of
driving a DAA (Data Access Arrangement - that's the transformer, filter and
amplifier to connect to the telephone line) directly.  We are using it for a
wireless application.  It supports the AT command set and also comes in a
FAX/modem part RC224ATF.  It is very easy to use.  In small quantities they
are about $10 from Marshall.  Does anyone know if this is the same part that
came out in PC modems years ago?

Another source is MX-COM.  They only seem to have serial interface parts so
you need a UART as they require proper timing of the serial data.  Actually
you don't need a UART since they have taken pains to make it tolerant of
sloppy bit timings but the data rate needs to be accurate.  The MX-COM parts
are cheaper than the Rockwell parts.  They have a web site with .pdf data
sheets.

Cermetek makes a complete modem module but it's really expensive.  It is
probably the easiest solution if you want a telephone modem.

What other sources of single chip modems have you found?

Is this what you wanted or are you trying to actually build your own modem?

At 09:51 PM 5/26/97 -0300, you wrote:
>Is there any aplication note for making an external modem. I'm shure
>that it's not that complex.
>
>